<!doctype html>
<!--
Copyright 2016 The Chromium Authors. All rights reserved.
Use of this source code is governed by a BSD-style license that can be
found in the LICENSE file.
-->
<html>
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, user-scalable=no">
    <meta name="mobile-web-app-capable" content="yes">
    <meta name="apple-mobile-web-app-capable" content="yes">

    <!-- Origin Trial Token, feature = WebVR (For Chrome M59+), origin = https://webvr.info, expires = 2017-10-13 -->
    <meta http-equiv="origin-trial" data-feature="WebVR (For Chrome M59+)" data-expires="2017-10-13" content="Aqw0TUvp8CwZmgIS50pM1blhzy05y7OkBeW3AQQGjer4KuKV0p13xfrRbe2bT8B1+DgRW0O3Dda0yOjcL46GBwgAAABMeyJvcmlnaW4iOiJodHRwczovL3dlYnZyLmluZm86NDQzIiwiZmVhdHVyZSI6IldlYlZSMS4xIiwiZXhwaXJ5IjoxNTA3ODU5MDE4fQ==">

    <title>04b - Simple Mirroring pt. 2</title>

    <!--
      This sample demonstrates how to restrict a simple mirror of VR content
      (using PreserveDrawingBuffer) to only show the contents of a single eye.
    -->

    <style>
      body {
        background-color: black;
      }

      #canvas-clip, #webgl-canvas {
        box-sizing: border-box;
        height: 100%;
        left: 0;
        margin: 0;
        position: absolute;
        top: 0;
        width: 100%;
      }

      #canvas-clip.presenting {
        /* This property allows the canvas-clip div to hide the parts of the
        WebVR canvas that extend past it's bounds without adding scrollbars*/
        overflow: hidden;

        /* These center the div on the screen */
        bottom: 0;
        right: 0;
        margin: auto;
      }

      .presenting #webgl-canvas {
        /* By making the canvas 200% as wide as it's parent we'll only see the
        left eye's content. The rest will be cropped by the parent div */
        width: 200%;
      }
    </style>

    <!-- This entire block in only to facilitate dynamically enabling and
    disabling the WebVR polyfill, and is not necessary for most WebVR apps.
    If you want to use the polyfill in your app, just include the js file and
    everything will work the way you want it to by default. -->
    <script>
      var WebVRConfig = {
        // Prevents the polyfill from initializing automatically.
        DEFER_INITIALIZATION: true,
        // Ensures the polyfill is always active when initialized, even if the
        // native API is available. This is probably NOT what most pages want.
        ALWAYS_APPEND_POLYFILL_DISPLAY: true,
        // Polyfill optimizations
        DIRTY_SUBMIT_FRAME_BINDINGS: true,
        BUFFER_SCALE: 0.75,
      };
    </script>
    <script src="js/third-party/webvr-polyfill.js"></script>
    <script src="js/third-party/wglu/wglu-url.js"></script>
    <script>
      // Dynamically turn the polyfill on if requested by the query args.
      if (WGLUUrl.getBool('polyfill', false)) {
        InitializeWebVRPolyfill();
      } else {
        // Shim for migration from older version of WebVR. Shouldn't be necessary for very long.
        InitializeSpecShim();
      }
    </script>
    <!-- End sample polyfill enabling logic -->

    <script src="js/third-party/gl-matrix-min.js"></script>

    <script src="js/third-party/wglu/wglu-program.js"></script>
    <script src="js/third-party/wglu/wglu-stats.js"></script>
    <script src="js/third-party/wglu/wglu-texture.js"></script>

    <script src="js/vr-cube-sea.js"></script>
    <script src="js/vr-samples-util.js"></script>
  </head>
  <body>
    <div id="canvas-clip">
      <canvas id="webgl-canvas"></canvas>
    </div>
    <script>
      /* global mat4, VRCubeSea, WGLUStats, WGLUTextureLoader, VRSamplesUtil */
      (function () {
      "use strict";

      var vrDisplay = null;
      var frameData = null;
      var projectionMat = mat4.create();
      var viewMat = mat4.create();
      var vrPresentButton = null;

      // ================================
      // WebVR-specific code begins here.
      // ================================

      // WebGL setup.
      var gl = null;
      var cubeSea = null;
      var stats = null;

      function onContextLost( event ) {
        event.preventDefault();
        console.log( 'WebGL Context Lost.' );
        gl = null;
        cubeSea = null;
        stats = null;
      }

      function onContextRestored( event ) {
        console.log( 'WebGL Context Restored.' );
        initWebGL(vrDisplay ? vrDisplay.capabilities.hasExternalDisplay : false);
      }

      var webglCanvas = document.getElementById("webgl-canvas");
      webglCanvas.addEventListener( 'webglcontextlost', onContextLost, false );
      webglCanvas.addEventListener( 'webglcontextrestored', onContextRestored, false );

      var canvasClip = document.getElementById("canvas-clip");

      function initWebGL (preserveDrawingBuffer) {
        var glAttribs = {
          alpha: false,
          antialias: true,
          preserveDrawingBuffer: preserveDrawingBuffer
        };
        var useWebgl2 = WGLUUrl.getBool('webgl2', false);
        var contextTypes = useWebgl2 ? ["webgl2"] : ["webgl", "experimental-webgl"];
        for (var i in contextTypes) {
          gl = webglCanvas.getContext(contextTypes[i], glAttribs);
          if (gl)
            break;
        }
        if (!gl) {
          var webglType = (useWebgl2 ? "WebGL 2" : "WebGL")
          VRSamplesUtil.addError("Your browser does not support " + webglType + ".");
          return;
        }
        gl.clearColor(0.1, 0.2, 0.3, 1.0);
        gl.enable(gl.DEPTH_TEST);
        gl.enable(gl.CULL_FACE);

        var textureLoader = new WGLUTextureLoader(gl);
        var texture = textureLoader.loadTexture("media/textures/cube-sea.png");
        cubeSea = new VRCubeSea(gl, texture);
        var enablePerformanceMonitoring = WGLUUrl.getBool(
            'enablePerformanceMonitoring', false);
        stats = new WGLUStats(gl, enablePerformanceMonitoring);

        window.addEventListener("resize", onResize, false);
        onResize();
        window.requestAnimationFrame(onAnimationFrame);
      }

      function onVRRequestPresent () {
        vrDisplay.requestPresent([{ source: webglCanvas }]).then(function () {
        }, function (err) {
          var errMsg = "requestPresent failed.";
          if (err && err.message) {
            errMsg += "<br/>" + err.message
          }
          VRSamplesUtil.addError(errMsg, 2000);
        });
      }

      function onVRExitPresent () {
        if (!vrDisplay.isPresenting)
          return;

        vrDisplay.exitPresent().then(function () {
        }, function () {
          VRSamplesUtil.addError("exitPresent failed.", 2000);
        });
      }

      function onVRPresentChange () {
        if (vrDisplay.isPresenting) {
          if (vrDisplay.capabilities.hasExternalDisplay) {
            VRSamplesUtil.removeButton(vrPresentButton);
            vrPresentButton = VRSamplesUtil.addButton("Exit VR", "E", "media/icons/cardboard64.png", onVRExitPresent);
            canvasClip.classList.add("presenting");

            // Set the size to half the width and height of the eye's render
            // target. This makes the image proportional while also reducing the
            // draw costs of mirroring it to the screen.
            var leftEye = vrDisplay.getEyeParameters("left");
            canvasClip.style.width = (leftEye.renderWidth/2) + "px";
            canvasClip.style.height = (leftEye.renderHeight/2) + "px";
          }
        } else {
          if (vrDisplay.capabilities.hasExternalDisplay) {
            VRSamplesUtil.removeButton(vrPresentButton);
            vrPresentButton = VRSamplesUtil.addButton("Enter VR", "E", "media/icons/cardboard64.png", onVRRequestPresent);

            // Reset the div to it's default size when we're done presenting.
            canvasClip.classList.remove("presenting");
            canvasClip.style.width = "";
            canvasClip.style.height = "";
          }
        }

        // Make sure the canvas is resized AFTER we've updated the container div.
        onResize();
      }

      if (navigator.getVRDisplays) {
        frameData = new VRFrameData();

        navigator.getVRDisplays().then(function (displays) {
          if (displays.length > 0) {
            vrDisplay = displays[displays.length - 1];

            if (vrDisplay.capabilities.canPresent)
              vrPresentButton = VRSamplesUtil.addButton("Enter VR", "E", "media/icons/cardboard64.png", onVRRequestPresent);

            // For the benefit of automated testing. Safe to ignore.
            if (vrDisplay.capabilities.canPresent && WGLUUrl.getBool('canvasClickPresents', false))
              webglCanvas.addEventListener("click", onVRRequestPresent, false);

            window.addEventListener('vrdisplaypresentchange', onVRPresentChange, false);
            window.addEventListener('vrdisplayactivate', onVRRequestPresent, false);
            window.addEventListener('vrdisplaydeactivate', onVRExitPresent, false);

            initWebGL(vrDisplay.capabilities.hasExternalDisplay);
          } else {
            initWebGL(false);
            VRSamplesUtil.addInfo("WebVR supported, but no VRDisplays found.", 3000);
          }
        }, function () {
          VRSamplesUtil.addError("Your browser does not support WebVR. See <a href='http://webvr.info'>webvr.info</a> for assistance.");
        });
      } else if (navigator.getVRDevices) {
        initWebGL(false);
        VRSamplesUtil.addError("Your browser supports WebVR but not the latest version. See <a href='http://webvr.info'>webvr.info</a> for more info.");
      } else {
        initWebGL(false);
        VRSamplesUtil.addError("Your browser does not support WebVR. See <a href='http://webvr.info'>webvr.info</a> for assistance.");
      }

      function onResize () {
        if (vrDisplay && vrDisplay.isPresenting) {
          var leftEye = vrDisplay.getEyeParameters("left");
          var rightEye = vrDisplay.getEyeParameters("right");

          webglCanvas.width = Math.max(leftEye.renderWidth, rightEye.renderWidth) * 2;
          webglCanvas.height = Math.max(leftEye.renderHeight, rightEye.renderHeight);
        } else {
          webglCanvas.width = webglCanvas.offsetWidth * window.devicePixelRatio;
          webglCanvas.height = webglCanvas.offsetHeight * window.devicePixelRatio;
        }
      }

      function onClick () {
        // Reset the background color to a random value
        if (gl) {
          gl.clearColor(
            Math.random() * 0.5,
            Math.random() * 0.5,
            Math.random() * 0.5, 1.0);
        }
      }

      // Register for mouse restricted events while in VR
      // (e.g. mouse no longer available on desktop 2D view)
      function onDisplayPointerRestricted() {
        if (webglCanvas && webglCanvas.requestPointerLock) {
          webglCanvas.requestPointerLock();
        }
      }

      // Register for mouse unrestricted events while in VR
      // (e.g. mouse once again available on desktop 2D view)
      function onDisplayPointerUnrestricted() {
        var lock = document.pointerLockElement;
        if (lock && lock === webglCanvas && document.exitPointerLock) {
          document.exitPointerLock();
        }
      }

      VRSamplesUtil.addVRClickListener(onClick);
      webglCanvas.addEventListener("click", onClick, false);
      window.addEventListener('vrdisplaypointerrestricted', onDisplayPointerRestricted);
      window.addEventListener('vrdisplaypointerunrestricted', onDisplayPointerUnrestricted);

      function onAnimationFrame (t) {
        // do not attempt to render if there is no available WebGL context
        if (!gl || !stats || !cubeSea) {
          return;
        }

        stats.begin();

        gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);

        if (vrDisplay) {
          vrDisplay.requestAnimationFrame(onAnimationFrame);

          vrDisplay.getFrameData(frameData);

          if (vrDisplay.isPresenting) {
            gl.viewport(0, 0, webglCanvas.width * 0.5, webglCanvas.height);
            cubeSea.render(frameData.leftProjectionMatrix, frameData.leftViewMatrix, stats, t);

            gl.viewport(webglCanvas.width * 0.5, 0, webglCanvas.width * 0.5, webglCanvas.height);
            cubeSea.render(frameData.rightProjectionMatrix, frameData.rightViewMatrix, stats, t);

            vrDisplay.submitFrame();
          } else {
            gl.viewport(0, 0, webglCanvas.width, webglCanvas.height);
            mat4.perspective(projectionMat, Math.PI*0.4, webglCanvas.width / webglCanvas.height, 0.1, 1024.0);
            cubeSea.render(projectionMat, frameData.leftViewMatrix, stats, t);
            stats.renderOrtho();
          }
        } else {
          window.requestAnimationFrame(onAnimationFrame);

          // No VRDisplay found.
          gl.viewport(0, 0, webglCanvas.width, webglCanvas.height);
          mat4.perspective(projectionMat, Math.PI*0.4, webglCanvas.width / webglCanvas.height, 0.1, 1024.0);
          mat4.identity(viewMat);
          cubeSea.render(projectionMat, viewMat, stats, t);

          stats.renderOrtho();
        }

        stats.end();
      }
      })();
    </script>
  </body>
</html>
